The distribution and regeneration of Boswellia papyrifera (Del.) Hochst. in Eritrea | Tropical Resource Management Papers
2001
Ogbazghi, Woldeselassie | Kostense, Piet | Ogbazghi, Woldeselassie
Boswellia payrifera (Del). Hochst. is a deciduous gum-producing multipurpose perennial tre species growing in Sudanian and Sahelian regions. The tree is tapped on the stem for oleo-gum called olibabum (tree frankinscense). Land clearing for agriculture and un-regulated grazing are threatening the future of the natural Boswellia woodlands in Eritrea. The present study reports on the distribution of the species and the factors determining its distribution limits in Eritrea, the structure and dynamics of Boswellia populations, including the natural regneration, and the factors causing the decline of Boswellia woodlands. Measures ehich can reverse this situation are indicated. At macro-level, the distribution of the species is limited to the southwestern and southern parts of the country between 800-1850 m altitude receiving a mean annual rainfall of 375-700 mm with a dependable length of growing period of 45-100 days. At micro-level, the abundance and distribution of the species is affected by (in order of importance): altitude, land use intensity, soil organic matter, and to lesser extent silt and pH. Tree development studies show that trees in the low-lands are twie as high as those in highlands. Tree populations show lack of regneration. The present system of intensive annual tapping throughout the dry season leads to low production of non-viable seeds. Also, seedlings and saplings are usually destroyed by livestock. Enclosures in which tapping and grazing is not allowed effectively promoted natural regneration.
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